Method and apparatus for decreasing oil and gas ratio of a petroleum well



Jan. 15, 1963 3,073,393

3 Sheets-Sheet 1 A. L. SMITH METHOD AND APPARATUS FOR DECREASING OIL ANDFiled July 2, 1959 GAS RATIO OF A PETROLEUM WELL dwarf Arr RNEVJ' A. L.SMITH PARATUS Jan. 15, 1963 ,073,393 METHOD AND AP FOR DECREASING 011.AND GAS RATIO OF A PETROLEUM WELL 3 Sheets-Sheet 2 Filed July 2, 1959Jan. 15, 1963 Filed July 2, 1959 mum" m A. L. SMITH METHOD AND APPARATUSFOR DECREASING OIL AND GAS RATIO OF A PETROLEUM WELL 3 Sheets-Sheet 5Aframvsm United States Patent This invention relates to methods andapparatus for decreasing the oil and gas ratio of a petroleum well.

In the production of oil and gas wells large volumes of gas are producedper barrel of oil. The relationship of the amount of oil to the amountof gas is known in the industry as the gas-oil ratio.

In all major petroleum producing states, state agencies control theproduction of oil and gas, and for conservation reasons refuse to permitthe production of oil with an excessive gas-oil ratio unless the wellowner can find a market for the gas. This is not always possible due tothe cost of gathering and transmitting the gas. While the amount of gasis large in comparison to the amount of oil produced in many wells, thetotal amount of gas produced is not such as to attract purchasers ofgas.

It has been known for years that the gas-oil ratio might be reduced byemploying chokes to maintain a back pressure on the formation. However,production of the well with chokes which will reduce the gas-oil ratioto a required value will not always permit the operator to produce theamount of oil allocated to his well by the state agency, known as theallowable.

It is an object of this invention to provide a method and apparatus forreducing the gas-oil ratio of wells without reference to the rate offlow of the well.

Another object is to provide a method and apparatus for reducing thegas-oil ratio of wells by preventing the swirling effect of incomingfluids, preferably over the full diameter of the casing, and at leastimmediately adjacent the opening into the production tubing.

Another object is to provide a method and apparatus for reducing thegas-oil ratio of wells by preventing swirling of fluids as they enterthe production tubing.

Other objects, features and advantages of this invention will beapparent from the drawings, specification and claims.

Modern day wells are completed by first setting a casing opposite theproducing formation and then perforating the casing and formation with agun. For various reasons the perforations are made in a manner whichcauses the gas to swirl as it flows into the casing. For instance, thegun may be off center at the time of firing so that the holes are notpositioned on radiuses of the casing. Fluid striking the side wall ofthe casing at an angle is caused to immediately swirl. The presence ofthe production tubing accentuates this swirling action as the incominggas strikes the tubing, and tends to flow in a circular manner throughthe casing tubing annulus.

The action described above results in the liquid within the hole movingin a swirling fashion and being constantly thrown away from the entranceto the production tubing. In other words, a vortex is formed in theliquid. The result is that the gas flows to the tubing in a swirlingfashion constantly pushing the liquid in the hole away from the tubing,and a high gas-oil ratio is obtained.

It has been found that if this swirling action is prevented, the gas-oilratio will be substantially reduced. The swirling action of the gas asit flows to the inlet of the production tubing may be readily overcomeor prevented by placing an obstruction in the well which will interruptthe swirling action. For instance, a vane may be placed in the casingtubing annulus in the path of the swirling fluid to interrupt thecircular flow of the fluid. This interrupting vane should be providedimmediately adjacent the inlet to the production tubing, as this willstraighten flow of the fluid immediately bemore it enters the tubing. Ifdesired, the inlet to the tubing may be provided with a vane which willstraighten the fluid as it enters the tubing and prevent swirling actionwhich might be induced by gas flowing into the tubing. Where a presetpacker prevents placement of other types of obstruction in the well,vanes may depend from the tubing and be stabbed through the packer.

Reference is now made to the drawings, wherein illustrative apparatus isshown for carrying out this invention, and wherein like referencenumerals indicate like parts:

FIGURE 1 is a view in vertical cross section through a cased wellshowing a stabilizer and flow tubing therein in elevation;

FIGURE 2 is a view along the lines 22, of FIG- URE 1;

FIGURE 2a is a View along the lines 2--2 of FIG- URE 1 with thestraightening vanes omitted and indicating the swirling action of fluidwhich will increase the gas-oil ratio;

FIGURE 3 is a view similar to FIGURE 1 showing a modified form of thisinvention;

FIGURE 4 is a view along the lines 44 of FIG- URE 3;

FIGURE 5 is a view in section through a Well hole and showing inelevation a modified form of stabilizer to be used where the productionpacker is to be positioned in the hole independent of the productiontub- FIGURE 6 is a view similar to FIGURE 5 showing the packer andtubing in place;

FIGURE 7 is a View along the 1ine 7-7 of FIGURE 5; and

FIGURE 8 is a diagrammatic view partly in section and partly inelevation of a further modified form of this invention.

Reference is first made to FIGURE 2a which illustrates the action of thewell fluid when the well is not equipped with this invention. It will benoted that the holes in the casing were perforated by an ofiE-center gunwhich results in a circular motion of the well fluid as it flows intothe casing tubing annulus.

In FIGURE 2 this same well is illustrated with intenrupting vanes inaccordance with this invention, and it will be seen that the well fluidis forced to flow vertically in a casing tubing annulus and cannot flowin a circular fashion as the vanes extend over a substantial percentageof the casing tubing annulus.

The vanes may be positioned in the well in any desired manner. In FIGURE1, a tubular body 10 is shown secured to the lower end of productiontubing 11. The tubular body may be a length of tubing of the same sizeas the production tubing 11. A plurality of vanes 12 are carried on body10. It will be appreciated that only one vane is necessary to stop thecircular movement of well fluid, 'but a number are preferred as theywill center the tubing in the perforate section 15 of casing 13 andprevent any swirling action from occurring. They will also prevent thehigh velocity fluid striking them from cutting either the tubing or theopposite side of the casing when they are in the direct path of thefluid entering the well from the formation.

While the vanes are shown opposite the perforations 14 in the perforatesection 15 of casing 13, it will be appreciated that they should bepositioned closely adjacent the inlet 16 of the tubular body 10. Thiswill prevent the swirling action at the inlet to the tubular body Itwhich is the critical point. Of course, if the vanes are extended to theperforated section of the casing, all swirling action will be stopped.However, the perforated formation may extend over a substantialdistance, and in such cases the stabilizer of this invention willprovide the desired results by the vanes being positioned adjacent theinlet to the body of the stabilizer.

The vanes 12 may be welded or otherwise secured to the tubular body 10,and preferably extend radially almost to the perforate section 15 ofcasing 13. The vanes have a substantial longitudinal dimension toprevent the tendency of the well fluid in the casing-tubing annulus toswirl. For instance, a stabilizer for a 2%" tubing might employ vanesextending approximately fifty inches in length, to insure completeinterruption of any swirling action.

Referring now to FIGURES 3 and 4, there is shown a stabilizer which isreadily adapted to use in different sized holes. In this instance, asingle central body 17 is adapted to be secured to the lower end of theproduction tubing 11, and has provided at circumferentially spacedpoints ears or vertically extending flanges 18 to which the vanes may beattached. The detachable vanes 19 may be warehoused in various sizes andassembled with the body 17 when needed. This will substantially reducethe inventory of parts, and reduce the storage area necessary towarehouse these parts. The vanes may be secured to the flanges 18 in anydesired manner, such as by the bolt and nut connections indicatedgenerally at 21.

In order to obtain maximum flow through the stabilizer body with minimumturbulence, there is provided within the body 17 a flow nozzle indicatedgenerally at 22. This nozzle has a constant diameter portion 23 which issealingly secured to the tubular body 17 by one or more spanners 24-. Atthe inlet end of the nozzle a frustroconical portion 25 is provided toobtain the desired nozzle action. Within the frusto-conical portion 25,one or more vanes 26 are provided to prevent any swirling action of thewell fluid as it enters the nozzle 22.

In the use of either of the FIGURE 1 or FIGURE 3 forms of stabilizer,the tubing is made up with a conventional hook wall packer shownschematically at 27, and the stabilizer of either FIGURE 1 or FIGURE 3is made up on the free or lower end of the production tubing 11. Thetubing is run into the hole, the production packer 27 set, and thetubing suspended at the desired elevation for production through thecasing perforations 14.

As the well fluid enters through the perforations 14, it will be forcedto flow vertically in a non-circular path by the vanes downwardly to theinlet of the stabilizer. As the swirling action normally present in thehole will be prevented, the fluid level will be immediately adjacent theinlet to the stabilizer, no vortex will be present in the surface of theliquid in the hole, and a relatively low gas-oil ratio will be obtained.

It is sometimes desired to leave the production packer within the casingand provide for the tubing to be pulled. In this instance, the packer isusually set in the hole before the tubing is run. For well completion ofthis type, the stabilizer shown in FIGURE 5 may be used. This stabilizerhas a body provided in part by an upper portion 28 which is tubular inform to provide a central bore 29 through which the production tubing 31may pass. The remainder of the body is provided by a lower member 32which has a diameter preferably the same as the outer diameter oftubular member 28.

To prevent the swirling action of fluid flowing into the well, one ormore vanes 33 extend between the body portions 28 and 32. The vanes havea substantial radial dimension to extend them to points adjacent thecasing 34, and have a substantial longitudinal dimension to insureinterruption of any swirling action of the fluid passed to the tubing31. While there may be a slight space between the several vanes 33 andthe tubing, the swirling action will be substantially interrupted due tothe centrifugal forces induced by the swirling fluid urging it outwardlyinto contact with the vanes 33- However, if desired, the vanes could bepositioned more closely to the tubing than shown in the drawing toprevent any possibility of a swirling action. The weight of thestabilizer and frictional contact between it and the casing, tubing,and/ or plug 35 hold the stabilizer against any substantial rotation.

In the use of this form of the invention, the stabilizer may be droppedinto the hole and will pass through the fluid in the hole to the bottomof the hole, where it will rest on the cement plug 35 as shown.Thereafter, the packer 36 may be run in the hole and landed above theproducing formation 37. Then the tubing 31 is run into the hole andpasses through the packer and into the stabilizer, so that fluid flowingto the inlet 38 of the tubing will be prevented from swirling at theentrance to the tubing, in accordance with this invention. Of course,the nozzle shown in FIGURE 3 might be employed at the inlet of tubing31, if desired.

Referring now to FIGURE 8, another modification of this invention isshown. In some instances a packer is set in the well and thereafter itis desirable to run a tubing through the packer. If at this time it isdesirable to provide vanes for decreasing the swirling action ofincoming fluid, the apparatus of FIGURE 8 may be used. While it will notentirely stop the swirling action of incoming fluids, it will stopswirling action of fluids immediately adjacent the inlet of the body atthe point at which the tubing is being loaded, and this will de creasethe gas-oil ratio.

In conventional manner the well shown in FIGURE 3 has been cased with acasing 39 and perforated as at 39a. A packer 41, which may be of thewell known wireiine type, has been set in the well. The productiontubing 42 is shown being run in the well, and will be lowered until thetubing packer seat 43 engages the casing packer.

As shown in dashed outline, a flow nozzle 44 may be provided in thetubing, if desired. This flow nozzle could be identical with the flownozzle shown in FIG- URE 3, except that, in view of the vanes to bedescribed, it would not be necessary to provide vanes at the inlet tothe nozzle.

One or more vanes 45 are provided for preventing or reducing swirling orwell fluids. These vanes may be depended from the tubing 42 in anydesired manner, as by welding them to the open end of the tubing asshown. Preferably, the vanes extend into the interior of the tubing ashort distance to prevent swirl of fluid as it enters the mouth of thetubing. The portion 45a of the vanes extending into the tubing willfunction to straighten flow of fluid entering the tubing in a comparablemanner to the vane 26 in the FIGURE 3 embodiment.

Preferably, the vanes 45 are four in number and radiate from the centerline of the tubing out to the full outer diameter of the tubing 42. Byutilizing the full diameter of the tubing, substantial straightening offluid will be obtained, and yet the vanes 45 may be easily stabbedthrough the packer 41.

The vanes 45 have a substantial longitudinal dimension, that is,lengthwise of the tubing, to obtain substantial straightening of thewell fluids. While this type of vane will not preevnt all swirling inthe casing, as the incoming well fluids may rotate in the annulusbetween the vanes and the casing, they will stop swirling in the centerof the tubing and prevent the formation of a large vortex in the surfaceof the liquid within the well. The prevention of this vortex is theprimary consideration in decreasing the gas-oil ratio, and thereforeconsiderable decrease in the gas-oil ratio may be obtained by using thestructure shown in FIGURE 8.

In operation, the packer is first set and then the tubing 42 is run inthe well with the vanes 45 depending from its lower end. The vanes willbe positioned in the well by the tubing packer seat 43 landing on thepacker 41.

It will be apparent that, if desired, the stabilizer of FIGURES 5 and 6could be dropped in the well, the wireline packer set, and then thestabilizer of this figure inserted into the stabilizer of FIGURE 6. Theuse of both forms of stabilizers would absolutely prevent all swirlingin the section of casing which they occupy and in the inlet to thetubing.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof and various changes in the size,shape and materials, as well as in the details of the illustratedconstruction, may be made within the scope of the appended claim withoutdeparting from the spirit of the invention.

What is claimed is:

A flow control stabilizer for wells comprising, a tubu lar body adaptedto be secured to the lower end of a production tubing and conduct fluidthereto, at least one vane secured to the body and extending radiallytherefrom beyond said body, said vane having a substantial longitudinaldimension and preventing swirling of 6 well fluids about the body, anozzle providing an inlet into the lower end of the body, and at leastone vane in the nozzle preventing swirling of well fluids entering thenozzle.

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